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|
data Tree = Node Int | Branch [Tree]
toList :: Tree -> [Int]
toList (Node n) = [n]
toList (Branch ts) = concatMap toList ts
digits :: Int -> Int
digits n = floor $ logBase 10 (fromIntegral n) + 1
transform :: Tree -> Tree
transform (Node 0) = Node 1
transform (Node n)
| even (digits n) = Branch . map Node $ halves n
| otherwise = Node $ n * 2024
transform (Branch ts) = Branch $ fmap transform ts
halves :: Int -> [Int]
halves n = [ floor $ fromIntegral n / 10^x
, n `mod` 10^x
]
where
x = digits n `div` 2
parse :: String -> Tree
parse = Branch . map (Node . read) . words
flatten :: Tree -> Tree
flatten = Branch . map Node . toList
main :: IO ()
main = getLine
>>= print
. length
. toList
. (!!25)
. iterate (flatten . transform)
. parse
|
